This invention relates generally to shotshells and more particularly to a shotshell having a seal forming the end closure over the load of shot.
In the past, many methods of closing the end of a shotshell have been advanced. A folded over end of the shell forming a crimped end has been the most widely accepted form of end closure.
U.S. Pat. No. 3,055,302 discloses a plastic shotshell case having a star shaped crimp end closure. In addition, a polyethylene plug is friction sealed into the central hole in the star crimp by spin welding. This arrangement provides a rather strong, thick and solid end closure but may adversely affect the reloadability of such a casing.
Another example, U.S. Pat. No. 3,442,214 utilizes a rather thick, over shot card 9 of granulated cork impregnated with paraffin wax and a roll crimp end closure. The impregnated cork over shot card may provide a moisture seal over the shot; however, it introduces a substantial parasitic weight to the load.
One major difficulty with all of the prior art end closures is that the interior volume of the case is limited by the length of the tube remaining after the end is folded over or roll crimped onto the paper disk. With the advent of steel shot for waterfowl loads requiring an increased volume, it is desirable to maximize the interior case volume. Various ways of increasing the interior case volume include minimizing the basewad volume as in U.S. Pat. No. 4,867,066, assigned to the assignee of the present invention. Still additional ways of increasing the interior volume would be advantageous while creating a hermetic end seal.
It is therefore an object of the invention to provide a sealed end closure for an uncrimped and unfolded shotshell.
It is another object of the present invention to provide a simple, light weight moisture sealed shotshell having an increased volume that introduces minimal parasitic load.
It is a further object of the present invention to provide a moisture sealing end closure for a shotshell which may be ejected from the shotshell case through the barrel.
It is a still further object of the present invention to provide an end closure for a shotshell that has no adverse impact on the shot pattern.